Pulsator for milking machines



May. 30,v 1939. s, 1 ERLlNG l 2,160,651

PULSATOR FOR MILKING MACHINES Filed'Nov. 29, 1937 Patented May 30, 1939 UNITED STATES PATENT oFFicE PULSATOR FOR MILKING MACHINES Sven Johan Erling, Ncckeby, Sweden, assigner to The De Laval Separator Company, New York, N. Y., a corporation'of New Jersey Application November 29,1997, serial No. 176,982 In Sweden December 3, 1936 2 Claims.

partial vacuum is effected. In pulsators of the other type, of which that shown in the Forsberg Patent No. 2,042,300 is an example, the opening and closing of the said communications are effected by a number of poppet valves, which are l5 generally controlled by a diaphragm, one or more bellows, or the like.

'Ihe object of the pulsators is to effect pneumatic pulsations in the pressure existing in the annular chamber between the rigid wall of the teat cup and the flexible and elastic teat cup liner which during milking embraces the teat. 'I'he liner may sometimes become damaged, so that the milk leaks out into said chamber. Such milk nally penetrates into the pulsator and comes 5 into contact with its slides or valves and other movable parts.

Experience has shown, however, that milk leaking into the pulsator causes much more serious disturbances in the operation of a pulsator of the rim poppet valve type than in the operation of a pulsator of the slide type. This is particularly the case if the valves of the poppet valve type of pulsator are controlled by one or two diaphragms or bellows, which when leakage occurs are also s exposed to the action of the milk. Thecollected or deposited milk dries between the period of milking and on the occasion of the next milking it is found that the pulsator does not operate. Y It then becomes necessary to disassemble the n pulsator for cleaning, that is, for removal of the dried milk. With a pulsator of the slide type this is a very simple job which can be elected on the spot by simply taking out and wiping the slide and the bore. To remove the dried milk from a `poppet valve pulsatorespecially if it be provided with bellows-.is however a complicated and diicult operation, it being in most cases Ynecessary to return the pulsator to the factory for the necessary renovation.

However, the use of one or two bellows for the control of the pulsator has advantages so great that it is undesirable to sacrifice them. A system of bellows or diaphragms of this kind has, however, a small reversing power in relation to u the frictional resistances to which the slide may be exposed. Heretofore diaphragms have been used to advantage `for the reversing of valves in which the frictional resistance to their movement is comparatively inconsiderable. While it is possible to build a slide with, for instance, a 5 diaphragm acting thereon for reversing the slide, the frictional resistance to the operation of the slide would be such that the pulsator would not "offer a sufficient degree of safety of operation.

Further, the bellows or the diaphragm would not flo be protected from coming into contact with the milk when it leaks into thel pulsator.

The present invention embodies a pulsator which combines the advantages of the slide pulsator and the bellows pulsator, in that a primary llli bellows or diaphragm-controlled pulsator built in the pulsator housing generates the primary pulsations which in turn act on a secondary pulsator of the slide type, and in which provision is made to insure that milk entering the second- 120 ary pulsator does not penetrate into the primary pulsator.

In the accompanying drawing, which illustrates a preferred embodiment of the invention- Fig. 1 is a vertical sectional view showing all 25 the details of construction except the' means to prevent leakingmilk penetrating to the primary pulsator. Fig. 2 is a partial transverse sectional view on the line 2 2 of Fig. 1 of a modification including means to prevent such milk penetration.

The primary pulsator comprises two expansible and contractible fluid containers, which may have the shape of bellows I, I. These bellows are` contained in air chambers I8 and I9. 35 'Ihe bellows may be secured in annular grooves formed in projections from opposite sides of the wall 20 separating chambers I8 and I9 and communicatefwith one another by means of a channel 40 formed in such wall. The channel may 40 be throttled byV making the channel of sufficiently small diameter or by contracting its central part or it may be adjustably throttled by means, for example, of a rod 4I threaded in the wall 20 and extending into the channel 40. A similar con- `-145 necting channel is disclosed in the Forsberg patent above mentioned. These bellows I, I, or one of them, may be connected by a rod 2 with a reversing mechanism 3 of known type, by means of which a slide valve 4 is operated. The slide 50 valve 4 is adapted to place a port 5 alternately in communication with a port 6 vand a port 1. The port 5 communicates with one end of the chamber 8 of the secondary pulsator. Ports 6 andl communicate respectively with a source of low pressure (partial vacuum) and a source of high pressure (atmosphere). A pulsating pressure is thus generated in the port 5 and pulsator chamber 8. It will be understood that the connection between the rod 2 and the valve l is such that the valve 4 will not begin to shift until after there has been a certain volume of flow between the bellows, after which it will shift quickly.

The chamber 8 shown in Fig. 1 is of that known type which comprises a cylindrical bore of greater diameter at one end than at the other while the slide valve 9 comprises a shank which has a sliding t in the smaller diameter section of the valve chamber and a head which has a sliding iit in the greater diameter section. The smaller diameter head of the valve is subject to constant atmospheric pressure through the opening i0 in one end wall of the casing. Since the large diameter head of the valve is subject to alternate atmospheric pressure and vacuum, the slide 9 is thereby reciprocated.

In the wall oi the chamber 8 are ports 30, 3l, 32, 33 and 34. Port 3U connects with a nipple I5 communicating with the pulsation chamber of one pair of teat cups I6, of which one is shown. Port 3i connects with a nipple I1 communicating with the other pair of teat cups. Port 32 connects with a nipple I4 which communicates with a source of partial vacuum. Ports 33 and 34 open respectively into chambers I8 and I9. The smaller diameter section ofv the valve 9 has a reduced or neck portion,.forming a chamber 23 adjacent the larger diameter section of the valve.

The two sections of the valve are provided with annular grooves II and I2 which are in constant communication with the atmosphere through an axial channel I3 and the opening I0.

When the valve 9 is in the position shown in Fig. 1, air chamber I8 andthe pulsation chambers of two of the teat cups are under vacuum, while the other air chamber I9 and the pulsation chambers of the othertwo teat cups are under atmospheric pressure. ,Ihese connections are reversed when the valve 9 is shifted to the right.

When there is atmospheric pressure in one air chamber I8, the bellows provided in this chamber is compressed and the airV contained therein is iorced over to the bellows in the other chamber, in which there is then a vacuum. As soon as the bellows in one chamber has been compressed and the bellows in the vother chamber has expanded to a certain degree, the slide lvalve 4 is reversed and thereby also the valve 9, which brings about a reversal of pressures in the chambers I8 and i9, so that the rod 2 starts moving in the opposite direction. Y

In Fig. 1 the nozzles communicating with the teat cup are shown, for the purpose of complete illustration, as positioned on the top of the secondary pulsation chamber. Y It is preferred, however, to have the nozzles projectvirom the side of the secondary pulsation chamber, as shown at I5 in Fig. 2, in order to more conveniently provide for free air ilow to and from chambers I8 and I9 while preventing inflow thereto of leaking milk. The means eiecting this object comprises a small diameter tube 22 extending from each of these chambers (Fig. 2 shows its application to chamber I8) into a chamber 2l communicating with the secondary pulsation chamber. Port 33 is eliminated, the tube 22 performing the function of that port as an air passage. Any 4milk `entering through the nipple I5 flows into the secondary pulsation chamber. A great accumulation of milk in the chamber 2l cannot take place and the level of the liquid cannot reach higher than to the position indicated by the fluid in Figure 2. The upper orifice of the tube 22 is therefore always free from milk, and the bellows in chamber I8 is consequently protected from contact with the milk. Similar means are provided ior connecting chamber I9 with high and low air pressure, while excluding flow of leaked milk thereinto. The port 5, which runs from the slide 4 of the primary pulsator, may be desirably connected in the same manner with the chamber 8, so that milk cannot flow from the latter to the former.

What I claim and desire to protect by Letters Patent is:

1..A Ymilking machineV pulsator comprising means providing air passages adapted to communicate respectively with sources of high and n low pressure, two air chambers, two expansible and contractable fluid containers positioned in the respective air chambers, a conduit allowing flow of fluid back and forth between said containers, saidcontainers and conduit forming a closed system, a pneumatically actuable slide valve adapted to connect the two chambers with the'high and low pressure passages respectively and reverse such connections, Valve mechanism operable to control the pneumatic actuation of Ythe slide valve, and means, operable by the conitainers during expansion and contraction thereof, due tov changes of pressure in their respective chambers, controlling the operation of said valve mechanism.

2. A milking machine pulsator comprising means providing air passages adapted to communicate with sources oi high and Vlow pressure, two air chambers, two expansible and contractable fluid containers positioned in the respective air chambers, a conduit allowing flow of fluid back and forth between said containers, said containers and conduit forming a closed system, teat cups, tubes connected with the respective teat cups, a secondary pulsation chamber having two pairs of passages, the two passages of one pair 5a.

connecting the valve chamber with respectively one air chamber and one teat cup and the two passages of the other pair connecting the valve chamber with respectively the other air chamof pressure in Vtheir respective chambers. con- 5;; trolling the operation of the last named valve mechanism.

VSAVEN JOHAN ERLING.

Yber and Vthe other teat cup, a pneumatically actur-jg: 

